In a typical 3-6 month interval appointment, the endocrinologist would measure a patient's hemoglobin A1c (HbA1c) to determine the quality of the last 3 months control. This value, is linearly correlated to mean glucose levels at that 3 months period and, therefore, can be predicted according to the measurements. We used anonymous records of glucose measurements to perform preliminary statistical analysis. Our results indicate that a patient's glucose level is a highly non-stationary process, with strong variations in both mean and standard deviation (SD) from one week to another. In many patients with excessive HbA1c, which are at levels that diabetic complications are likely to ensue, the endocrinologist is obligated to adjust the insulin dosage based on a review of the patient's most recent glucose values and the values of the past several weeks. Furthermore, since appointment timing is random and independent from the patient's measurements, random trends in glucose values may be identified that lead to different conclusions. For illustration, if a patient's appointment happens to occur when his glucose values randomly trend up, the endocrinologist may choose to increase insulin doses. On the other hand, if the appointment occurs at a time when the glucose levels trend down, he may act oppositely. The required frequency of follow-up and dose adjustment that yields better patient control is yet to be determined.